This Phase Ib Trial is Meant to Evaluate the Safety, Pharmacokinetics, Pharmacodynamics, and Immunogenicity Profiles of JYB1904 Injection in Adolescent Participants With Allergic Diseases.

This Study is a multicenter, single-arm, Phase Ib clinical study to evaluate the safety, pharmacokinetics, pharmacodynamics, and immunogenicity profiles of JYB1904 injection in adolescent participants aged 12-17 years

Inclusion Criteria:

• Adolescent study participants (both male and female) who are at least 12 years of age but under 18 years of age at the time of signing the Informed Consent Form (ICF).
• History of allergic diseases, including but not limited to food allergies, allergic rhinitis, allergic asthma, and chronic spontaneous urticaria.
• Body weight ≥ 30 kg at screening.
• Agreement to use effective contraception during the study and for 1 year following administration of the study drug.
• The trial participant and their parent or legal guardian are able to understand and voluntarily sign the Informed Consent Form, and are able to comply with study visits and related procedures.

Exclusion Criteria:

• Patients with a history of hypersensitivity to JYB1904 Injection, its excipients, or any anti-IgE therapy.
• Any severe or poorly controlled chronic disease (including but not limited to severe arrhythmia, ischemic heart disease, NYHA Class III/IV left ventricular failure, severe pulmonary disease, poorly controlled asthma, poorly controlled hypertension, poorly controlled diabetes, or poorly controlled hypothyroidism or hyperthyroidism) that, in the investigator's judgment, may compromise the safety of the trial participant.
• History of severe allergic reactions, such as anaphylactic shock.
• History of blood phobia, needle phobia, or difficulty with venipuncture; or abnormal skin at the administration site that may interfere with drug administration or the investigator's assessment (e.g., skin lesions, rashes, tattoos, etc.).
• Total blood loss or blood donation of ≥400 mL within 12 weeks prior to screening, or receipt of a blood transfusion within 12 weeks prior to screening.